<!doctype html>
<html lang="en">

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Bootstrap demo</title>
    <script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script>
    <link href="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.staticfile.org/twitter-bootstrap/4.3.1/js/bootstrap.min.js"></script>
</head>

<body>
    <div class="col-6 card p-5">
        <div class="bg-secondary mb-2 p-2" align="center">
            <h4>注册界面</h4>
        </div>
        <form role="form">
            <!-- 注册用户名 -->
            <div class="input-group mb-3">
                <div class="input-group-prepend">
                    <span class="input-group-text" id="basic-addon1">用户名</span>
                </div>
                <input type="text" class="form-control" placeholder="请输入用户名称" />
            </div>
            <!-- 密码 -->
            <div class="input-group mb-3">
                <div class="input-group-prepend">
                    <span class="input-group-text" id="basic-addon1">密码</span>
                </div>
                <input type="password" class="form-control" placeholder="请输入密码" />
            </div>
            <!-- 确认密码 -->
            <div class="input-group mb-3">
                <div class="input-group-prepend">
                    <span class="input-group-text" id="basic-addon1">确认密码</span>
                </div>
                <input type="password" class="form-control" placeholder="请输入确认密码" />
            </div>
            <!-- 选择城市 -->
            <div class="input-group mb-3">
                <div class="input-group-prepend">
                    <span class="input-group-text" id="basic-addon1">城市</span>
                </div>
                <select class="form-control" name="cities" id="cities">
                    <option value="0">天津</option>
                    <option value="1">北京</option>
                    <option value="2">上海</option>
                </select>
            </div>
            <!-- 注册按钮 -->
            <button type="button" class="btn btn-primary">Primary</button>
        </form>
    </div>
</body>

</html>